02:41 pm - One of those subjects......that I think I know about and then find out I've oversimplified: "Why Are Europeans White?" Or, as the author points out, the more correct phrasing: "Why northern Europeans are so oddly de-pigmented compared to everyone else on the globe."

The underlying essay (with more details and citations) is a good read, too: it also addresses a second puzzle, as to why Native American populations aren't as dark-skinned as are other populations from the same latitudes.